Analysis of Age of Information Under SR ARQ

An analytical derivation of age of information is provided for a data stream with sequential content transmitted over an error-prone channel, using a selective repeat automatic repeat request for error control. The impact of the error process and/or the round trip time on the resulting age of information is assessed. The analysis allows to generate the entire statistics of AoI. The results highlight consequences such as a mild correlation in the error process, where the error bursts are not significantly longer than the round trip time, causing a decrease in AoI. This can serve as a reference to devise retransmission-based error control that is efficient in terms of information freshness.